The invention generally relates to a process in which a food product to be packaged is converted from a soft, fluid-like state to a firmer state in two or more stages. More specifically, the passage of the food product through these stages is useful to provide the food product with desired flow characteristics as it moves through the packaging equipment, and for obtaining the desired finished product body and texture.
Food products which are fluid during processing, such as jelly, food sauces, and dessert gels, may be difficult to process or package. For example, if the food product is extruded, or is required to pass over rollers, its passage through a packaging machine may be physically impeded if the viscosity of the food product is too low (see, e.g., FIG. 5), also causing problems with proper weight control of the packages. Conversely, the product body and texture may be physically damaged if the viscosity is too high, as further described below.
It is known to add a thickener, such as a consumable gel, to food products. See, e.g., U.S. Pat. No. 5,567,454 to Bogdan, disclosing the use of gelatin, fruit pectin and food starch to provide jelly with “optimal flexibility and shape-retaining qualities” (col. 6, lines 12–14), and also disclosing a recessed container in which the finished product shape may be formed. However, food gels have typically been allowed to form in an undisturbed state in order to gel properly. If shear forces are applied to the gel as a result of packaging, the gel may be damaged, resulting in a fractured and unacceptable finished product, as has been described in U.S. Pat. No. 5,518,745 to Thota et. al as follows:                A problem with utilizing a continuous extrusion process to obtain a set extrudate is that when the product begins to set within the extruder, the possibility of degradation and physical break up of the extrudate during conveyance increases after the transition of the mixed ingredients from a liquid phase to a highly viscous solid or gel phase. The high viscosity of the setting gel increases shear forces throughout the extrudate as it is conveyed through the extruder. When the final mixture of the product is shear sensitive, the extrudate tends to degrade and break apart, at least sporadically, as it is conveyed through the extrusion die, significantly limiting the ability to continuously convey, shape, form and cut the extrudate in an efficient and continuous manner.(Col. 2, lines 7–20).        
Delaying gel formation until the product is in a packaged and finally-formed state, however, may present problems during earlier stages of the packaging process. The product may simply be too thin or runny to package properly as it passes through packaging machinery, such as high-speed slice forming equipment. Thus, problems have been encountered in packaging food products that are either relatively low or high in viscosity.
Some packaging equipment has been designed to move slowly enough to accommodate gel formation. With increasing food plant size and increased equipment automation, line speeds have increased. Packaging equipment requires fast throughputs to justify equipment costs. The food products made in these plants must not only be acceptable upon shipment, but must also be able to tolerate these rapid line speeds. Packaging equipment has been specially designed to allow the passage of solid state food products (see, e.g., the Thota patent, describing the use of a low viscosity fluid continuously flowing over a channel in an extrusion die to induce laminar flow of a gelled food product). However, it would be more economical to provide food products designed to progress through existing packaging machines than to specially design machines to handle fluid food products.
In addition, packaging materials or operations may require the food product itself to provide its own structural support, e.g., when a particular shape, such as a cookie or candy, is extruded and deposited on a tray.
Various gel shapes have been described in the patent literature. See, e.g., the Bogdan patent; EPO Patent Application 99-13 0904703 to Fassin et. al., “Slice-shaped filling for sandwiches”; U.S. Pat. No. 5,417,990 to Soedjak, describing multi-layered gelled products; and U.S. Pat. No. 5,783,241 to Bocabeille et. al., “Method For Producing Cylindrical Gel Food Products”, in which gelling is induced internally and externally of an extruded food product using a calcium bath. However, no provision for commercial high-speed processing and packaging of a food product using a multi-stage gel or thickener appears to be described.
Accordingly, it is an object of the present invention to provide a gelling or thickening system which will introduce sufficient integrity to a food product so as to facilitate packaging of the food product.
It is another object of the invention to provide a multi-stage gelling/thickening system that provides the food product with sufficient viscosity during all relevant stages of food product formation and/or food product packaging, while also imparting desired shape and texture characteristics to the food product.
It is a further object to provide a gelling/thickening system adaptable for use with existing packaging machines, such as extruder machines for packaging individual slices of food items, without the need to specially re-design such machines.
It is yet another object to provide a gelling/thickening system which provides a food product with desired viscosity to allow proper weight control over the food product packages.
It is still another object to provide a multiple-stage gelling/thickening system which is consumable, cost-efficient and environmentally friendly.